The concept of an electrically powered vehicle itself is not new and it is common knowledge that such a vehicle was in use as early as 1888. Although the fundamental theory of electric vehicles has been well known since that time, and there has been no lack of effort over the years, it should be noted that there have been few new developments in the state of the art. Most prior and contemporary electrically operated vehicles employ generally the same basic concepts both in design and in application.
Present day electrically powered vehicles are capable of relatively high speeds of operation and are efficient and economical to operate although the manufacturing cost may be relatively high at this time.
When compared to the present day internal combustion engine used to power vehicles, the electric vehicle has an energy consumption rate substantially equivalent to about 200 miles per gallon. This is a significant departure in energy consumption and is very much worth the effort of development to explore the potential for such vehicles.
A serious limitation of electrically powered vehicles is in the limited ability to store energy for use by the vehicle. The present structures and assemblies are capable of a range of about 100 miles in contrast to the 300 to 500 mile range of operation of vehicles powered by internal combustion engines. It should be noted that the range limitations of electrically powered vehicles as noted here contemplated the use of a reasonable limitation on batteries as the power reservoir. A compromise must be developed between load and power source and convenience of use and economy of manufacture. Also, a large increase in the numbers of batteries carried would define a concomitant increase in the charge time for the batteries which would result in a further inconvenience for the user.
The above design limitations have generally resulted in a failure to provide a vehicle with a combination of features competitive with the internal combustion power source and there has been no realization of a design which would provide an acceptable compromise for wide acceptance of an electrically powered vehicle.
The most acceptable compromise would, of course, involve the provision of an assembly of elements for an electrically powered vehicle which would be competitive in cost and range of use when compared to a vehicle powered by an internal combustion engine.
It should be noted that many diverse attempts have been made to provide an electrically powered vehicle with a range of operation approaching the internal combustion engine powered vehicle but none have been successful within reasonable design and use limitations. These attempts have involved, in part, the use of wind driven generators for recharging the battery power source; the use of a solar-cell battery which, of course, is recharged during conditions of light; the use of generators driven by motor actuated flywheels; the use of regenerative braking devices wherein the motor is momentarily converted into a generator during deceleration of the vehicle thereby generating a charging current which may be applied to the batteries to recharge them during use. In addition, assemblies of the type noted herein have been provided with small internal combustion driven generators to re-charge the batteries while the vehicle is in use during low battery demand operation of the vehicle. These attempts are of an evolutionary character and have not, to date, contributed significantly to the extension of the range of use of the vehicle sufficiently to make its use attractive when compared to vehicles powered by internal combustion engines.
Most prior attempts in development of electrically powered vehicles for extension of the range of operation have involved the use of a single set of batteries as the power source. To this extent, it can readily be seen that it has been necessary to attempt to recharge the battery while at the same time the batteries are being discharged during operation of the vehicle. This technique requires that the generating device be capable of producing more power than the motor consumes during operating conditions of the vehicle.